In Reply to: Prion Sizes posted by Mary Anne on January 6, 2005 at 1:42 pm:

Terry, I need to find a research source that can tell me the sizes of the prions involved in mad cow disease. Someone is putting out some research that they can filter the prions out of water. Sounds like BS to me.Mary Anne

hello mary anne,

lets hope it's not bs, to much BSeee going around anyway ;

Disposal of Prion-Contaminated Wastes from

Veterinary Laboratories

Dr. Donal O’Toole, Wyoming State Veterinary Laboratory, University of Wyoming

Safe disposal of prion-contaminated wastes became an issue for veterinary laboratories after a link was established between bovine spongiform encephalopathy (BSE) in European cattle and variant Creutzfeldt-Jakob disease (v-CJD) in people. The two most common transmissible spongiform encephalopathies of animals in the United States are scrapie (sheep and goats), and chronic wasting disease (mule deer, white-tailed deer, and elk). There is no evidence that scrapie or CWD are zoonotic diseases.

Most veterinary laboratories dispose of tissues and prion-contaminated wastes by incineration, alkali hydrolysis, or a combination of both. A small amount of prion-contaminated wastes, chiefly blood and fragments of tissue, enter necropsy drains during post-mortem examinations. Most of this material is processed at publicly owned treatment works. The insoluble, hydrophobic character of prions results in binding to particulates at all times – little or none remains in suspension. Currently there is no way to test for prions in wastewater.

Recently, Region 8 of the Environmental Protection Agency addressed the issue of laboratory disposal of potentially contaminated wastes in meetings with diagnosticians, state veterinarians, and wastewater managers. EPA region 8 prepared a draft policy (Discharges of Laboratory Waste to Publicly Owned Treatment Works (POTWs); January 10 2003) under the Industrial Pretreatment Program. This region has declared its intention to impose strict controls on the discharge of prion-contaminated materials from veterinary laboratories. In one instance, EPA Region 8 issued a cease-and-desist order to a Colorado Division of Wildlife necropsy facility that was testing deer for CWD. Such a policy, if strictly enforced, will impose considerable costs on veterinary laboratories. It may have impacts on current surveillance of hunter-harvested and sick deer that is necessary to establish the extent of CWD. The cost of routine necropsies on cervid species that die of all causes in CWD-endemic areas will be increased. The EPA has yet to perform a risk assessment to establish whether it is scientifically justified to impose a complete ban on prion-contaminated wastes in the sewer system. A risk assessment performed in England in the context of BSE estimated that, with worst case assumptions, an individual would have to consume 2 liters/day of tap water for 45 million years to have a 50% chance of infection1 The cost of retrofitting veterinary laboratories to comply with the regulations is likely to be several hundred thousand dollars per laboratory.

Even in the absence of data that CWD and scrapie are transmissible to people, given current public and regulatory concerns it will be prudent for veterinary laboratories to develop the capability to capture and inactivate prion-contaminated wastes, particularly from necropsy floors.

Water supplies at risk from BSE?A leading neurologist has warned the British Government's Inquiry into BSE (bovine spongioform encephalopathy or "mad cow disease") that drinking water supplies may be at risk of contamination. Dr Alan Colchester from Guy's Hospital in London gave evidence that the practice of allowing the spreading of sludge and liquid effluent from carcass rendering plants onto land could allow the infectious agent to enter underground aquifiers. The infectious agent of BSE is believed to be an extremely stable protein molecule (prion) which Dr Colchester believes may be able to survive the rendering process.

Dr Colchester is one of over 100 scientists and 300 civil servants expected to testify before the Inquiry which began in March this year. The terms of reference of the enquiry are "to establish and review the history of the emergence and identification of BSE and nvCJD (new variant Creutzfeld-Jakob Disease) in the United Kingdom, and of the action taken in response to it up to 20th March 1996; to reach conclusions on the adequacy of that response, taking into account the state of knowledge at the time".

The proceedings of the Inquiry have been made available on a World Wide Web site including detailed submissions by witnesses, descriptions of the roles of key people, and a chronology of events (http://www.bse.org.uk). The scientific evidence now appears conclusive that the 26 cases of nvCJD diagnosed in the UK since 1995 represent a distinct and new form of the disease, and that the characteristics of the nvCJD agent in animal infection experiments closely match those of the BSE agent.

However the possibility of transmission of BSE via water supplies would appear to be remote if the assumptions used in a recent paper by Gale et al. are accurate (1). The authors assessed the risks associated with a rendering plant processing BSE infected cattle and disposing of carcasses in the catchment of a chalk aquifier. The exercise was difficult because specific data on several aspects are lacking - there is no dose-reponse data for humans, no information on the behaviour of the BSE prion in water, no information on the effectiveness of barriers that may reduce movement of the prion into water, and limited data on the decay of infectivity in the environment.

To overcome these problems, the authors assessed the available data on the BSE agent and extrapolated using a series of worst case assumptions.

Infectivity to humansInfectivity is expressed as the 50% infectious dose (ID50) - the dose which would infect 50% of exposed individuals. Animal experiments have shown that infectivity is concentrated in the brain and spinal column of cattle, and a partial barrier to transmission exists between species so that about 1000 times the dose is needed to consitute an ID50 in a different species.

Infectivity via oral or gastric exposure is reduced about 100,000 fold compared to the intracerebral and intraperitoneal routes. Mice experiments have shown an oral ID50 of 6.3 g for BSE infected cattle brain, and the human ID50 is likely to be similar. For risk assessment, it is assumed the oral ID50 in humans is 1g, and each infected cow contains 1000 infectious doses (in the brain and spinal tissue). It is estimated that the oral ID50 in humans is equivalent to about 1013 prion molecules.

BSE in the aquatic environmentThe BSE prion protein is known to contain both hydrophobic and hydrophilic regions, and to be associated with cell membranes. It binds strongly to surfaces and is unlikely to exist in free solution in aqueous media. The authors conclude that as cattle carcasses decay the BSE agent would be released from cell membranes but would immediately bind to other particles.

While aggregates of BSE prion have been observed in some infected animals the maximum number of molecules in an aggregate is about 10 5 molecules, or about 108 fold less than the estimated human ID50. Therefore such aggregates are not likely to pose an infection risk and significant net dilution is likely to occur in aqueous environments.

Risks from ingestionAs the considerations above show that it would not be possible to ingest an entire infectious dose in a single esposure (eg a glass of water), the risks associated with small fractions of an ID50 were considered. Using the conventional linear low dose extrapolation commonly applied to microbial infections, it is calculated that ingestion of 108 prion molecules (the largest aggregate observed in infected animals) would correspond to a risk of 0.5 x 10-5, or 1 infection per 200 million people ingesting this dose.

The authors also discuss experimental evidence that a threshold may exist for infection - this would have the effect of further reducing the risk.

Environmental input of BSEThe sources of BSE input are described and it is noted that rendering is known to destroy 98% of infectivity. Residual infectivity has been demonstrated for MBM (meat and bone meal) but not tallow (fats).

Environmental barriersThe prion protein is resistent to proteolysis and heat degradation, but there is evidence that infectivity declines in buried carcasses. There are no data on the effect of conventional water chlorination on the BSE prion, but given the molecule's resistance to other chemical treatments it is unlikely that chlorination would reduce infectivity.

Quantitative risk assessmentThe above considerations are factored into a risk assessment with the following assumptions:

* the rendering plant processes 2000 BSE infected carcasses per week. * all infectivity is associated with MBM particles * effluent is treated by dissolved air flotation and sand filtration before discharge to chalk substrata, 80 m above an aquifier.

By modelling the removal of suspended solids (and attached BSE prion) it is concluded that only 0.004 human oral ID50 would be discharged from the plant each day.

It is assumed that the discharge from the plant would take at least 2 years to reach the aquifier layer and that infectivity would decline by 93% in this time. No allowance was made for removal of the BSE prion by filtration or binding to the chalk, although the authors believe this would be a major effect. A dilution factor of 83-fold is assumed for the borehole fed by the aquifier (ratio of plant discharge volume to water extraction volume).

On this basis the estimated concentration in the extracted water would be 3.0 x 10-11 of a human ID50 per litre of water. Assuming that consumers drink up to 2 litres of water per day, the daily risk of infection would be less than 10-10. An individual would require 45 million years of exposure to reach a cumulative exposure of one ID50. The application of worst case assumptions at each step means that even this risk estimate may be grossly over inflated.

The authors note that for quantitative risk assessment to be of practical use, there must be confidence that the outcome has a reasonable degree of accuracy. In this case the many unknowns in the data and the adoption of extreme worst case assumptions means that this is not the case. However the systematic consideration of each step in the process illustrate that even if some assumptions are incorrect (eg if there is no species barrier) the risk of transmission of BSE by drinking water is still remote.

While the incidence of diagnosed new cases of BSE in cattle in the UK and other European countries appears to be declining, researchers in Switzerland have found evidence that many cattle may be infected without displaying symptoms. A report in the 13th June issue of New Scientist described the development of a sensitive test to detect the abnormal protein which causes BSE.

Application of this test to brain tissue samples from 1761 apparently healthy cows slaughtered because they came from herds where cases of BSE had occurred, found 8 which tested positive. This suggests that BSE infection is present at a rate of 4.5 per 1,000 cows, yet the rate of symptomatic BSE in Switzerland is 100 times less than this. The Swiss government will now test cows from herds where BSE has not been reported, to determine whether they too may be infected.

Development of a risk assessment for BSE in the aquatic ...Click here to read Development of a risk assessment for BSE in the aquatic environment. Gale P, Young C, Stanfield G, Oakes D. WRe plc, Medmenham, Marlow, UK. ...www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve& db=PubMed&list_uids=9633645&dopt=Abstract - Similar pages

The BSE Inquiry / Statement No 493 Dr Paul Gale Issued 09/08/1999 ...

Name and qualificationsPaul Gale, M.A.(Oxon.), D. Phil.Background and CV1. I am a graduate of St Edmund Hall, University of Oxford and hold a Second Class (2.1)Bachelor’s Degree in Biochemistry. I obtained my Doctorate in Molecular Biophysicsfrom the Biochemistry Department at the University of Oxford.2. I am a Senior Scientist in the Microbiology Group at WRc plc.3. During my Ph.D., I investigated the interactions between integral membrane proteins andphospholipid molecules in lipid bilayer membranes using a variety of physical methods,including nuclear magnetic resonance. The lipids and proteins comprising biologicalmembranes are amphipathic molecules. The prion protein believed to be the agentresponsible in transmissible spongiform encephalopathies (TSEs) has similarities toamphipathic membrane-bound proteins. A major finding from my Ph.D. work was that anintegral membrane protein presents positive charges to the phospholipid headgroups atthe bilayer surface (Gale & Watts, 1992). I studied the effects of phospholipids on thedispersion properties of an integral membrane protein within the supporting bilayer(Sternberg et al. 1989; Gale, 1993a). I developed a detergent-free method formanipulating protein-lipid mixtures (Gale and Watts, 1991) and addressed the problemsof particle size on interpretation of results (Gale, 1993b).4. After completing my Ph.D., I joined the Microbiology Group at the Water ResearchCentre (now WRc plc) in 1989. My major area of research since 1992 has been themicrobiological quality of drinking water. I was responsible for projects to developstatistical models to predict where and when coliform bacteria are likely to occur indrinking water supplies. I am leading the work on the development of risk assessmentmodels for waterborne pathogens in drinking water. Risk assessment is the emergingmethod to predict the probability of illness from the small numbers of waterbornepathogens remaining in drinking water after treatment. My work has focused onaddressing the doses of pathogens to which drinking water consumers are exposed (Gale1996). I have recently investigated how drinking water treatment changes the spatialdistribution of micro-organisms (Gale et al. 1997).5. I have recently been invited to the editorial boards of two microbiological journals,namely Quantitative Microbiology and the Journal of Applied MicrobiologyInvolvement in BSE risk assessment6. I represented the Environment Agency as an Expert Witness at the Thruxted Mill PublicInquiry (Canterbury, February 1997). My Proof of Evidence covered the infectivity andthe biophysics of the BSE agent (Gale 1997). This combined both my knowledge ofmembrane proteins and microbiological risk assessment. Since that Inquiry, I have beeninvolved in several other BSE risk assessment studies for the Environment Agency andfor other organisations. These include:-· Risks of BSE transmission from land-spreading of rendering plant effluent.· Risk assessment for BSE infectivity in a discharge consent application for a renderingplant.· Assessment of risks from burial of BSE-infected carcasses at a landfill site.· Risks from disposal of MBM.1. I have presented some of this work on BSE and microbiological risk assessment at recentconferences:-· Integrating pathogen exposures and dose-response curves in microbiological riskassessment models for drinking water. Water Quality International Conference,Vancouver, June 1998.· Developments in microbiological risk assessment - from Cryptosporidium to BSE.Drinking Water Research 2000 Conference, University of Warwick, March 1998.· BSE in the aquatic environment: development of a risk assessment approach. Symposiumon Health-Related Water Microbiology, University of Warwick, September 1997.1. I have published a paper on BSE risk assessment in a peer-reviewed journal:-· Gale, P., Young, C., Stanfield, G. & Oakes, D. (1998) Development of a risk assessmentfor BSE in the aquatic environment - a review. Journal of Applied Microbiology, 84, 467-477.Scope of this Statement1. This statement presents the conclusions and assumptions regarding the infectivity and theenvironmental behaviour of the BSE agent. These are fundamental in the riskassessments for BSE in the aquatic environment undertaken by WRc for the EnvironmentAgency. Of particular importance is the identification of the hydrogeological anddrinking water-treatment barriers which will be effective at protecting public watersupplies from BSE. The conclusions developed here formed the basis of the riskassessments made by WRc and DNV for the Thruxted Mill rendering plant in Kent andhave been presented in documents prepared by me for the Public Inquiry held atCanterbury in February 1997 (Gale 1997). This statement summarises the evidence andarguments supporting those conclusions and assumptions. The comments made by MrDavid John Williams (WS No.18) and Dr Alan Colchester (WS No.19) in theirStatements of March 1998 to the BSE Inquiry in this respect are also dealt with here.2. This statement concludes with an overview of the likely risks from BSE to humansthrough drinking water at Thruxted Mill. A specific rebuttal of the paper (BSE and vCJD- The Kent/Hampshire Connection. Part II: The Smarden Spill and the Origin of BSE)written by Mr Williams is given in Appendix 1 (M70 Tab 4).Summary of the Conclusions and Assumptions developed in this Statement.3. These are:-{PRIVATE}Conclusion 1The oral ID50 for humans is 1 g of BSE-infected bovinebrain.Conclusion 2 BSE infectivity will be bound to particulates in theaquatic environment.Assumption 1 Through dispersion and dilution of BSE prions, drinkingwater consumers would only ever be exposed to minutesub-fractions of an ID50.Assumption 2 There is no threshold dose for prions and the relationshipbetween risk and dose is linear (at low doses).Conclusion 1. The oral ID50 for humans is 1 g of BSE-infected bovine brain.12. For the Thruxted Mill risk assessment, the oral ID50 for humans of 1 g of BSE-infectedbovine brain was calculated on the basis of the infectivity of BSE-infected bovine brainin mice. To relate the infectivity of BSE in mice to that in humans relies on informationon whether humans are more or less resistant to BSE than mice. This is dependent on themagnitude of the cow-to-man species barrier. There was considerable discussion at theThruxted Mill Public Inquiry about whether the worst case assumption was to assumethat the species barrier for humans was the same as that for mice or, worse still, that it didnot exist and that there was in fact no cow-to-man species barrier for the most susceptiblehumans (WS No.19 para 33). Available data at the time of that Inquiry suggested thathumans of one type of genetic makeup at least were more resistant to BSE than mice.However, there were no data available for humans of another genetic makeup whoappeared to be more susceptible to new variant CJD (WS No.19 para 38). Since theThruxted Inquiry, molecular data have been published (Raymond et al. 1997J/N/388/285) suggesting that there is indeed a species barrier even for the moresusceptible human genotype. The evidence regarding the magnitude of the cow-to-manspecies barrier is now summarised.The cow-to-man species barrier.1. Experiments in which the human prion protein (PrP) gene has been expressed in micesuggest that some humans at least are more resistant to BSE agent than mice (Hope 1995J/N/378/761; Collinge et al. 1995 J/N/378/779). Thus, while transgenic mice expressinghuman PrPC were rapidly infected by intracerebral challenge of CJD-infected humanbrain, none of those mice (Hope pers comm. February 1997) have been infected bychallenge with BSE-infected bovine brain. In contrast, wild type mice expressing murinePrPC were infected by intracerebral challenge with BSE-infected bovine brain. Results ofin vitro experiments in which human PrPC was challenged with BSE prions, PrPBSE, arealso consistent with a high cow-to-man species barrier (Raymond et al. 1997J/N/388/285). A worst case, therefore, would be to assume that the cattle-to-man speciesbarrier is no higher than the barrier between cattle and mice and that man is no moreresistant than mice to BSE infection (Kimberlin 1996 M8A Tab43). Since the oral ID50for mice is 6.3 g (Kimberlin 1996 M8A Tab43), this would mean that as a worst case thehuman oral ID50 would also be about 6 g of infected brain from a bovine with clinicalsymptoms. The WRc risk assessment takes a cautious approach and assumes that thehuman oral ID50 is just 1 g of BSE-infected bovine brain.

East Hills, N.Y., United States, Wednesday, December 08, 2004 -- (Business Wire India) -- The latest developments on the use of membrane filtration to remove infectious prions to enhance the safety of biologics and therapeutics is the subject of a major presentation on Tuesday at the IBC international conference on Transmissible Spongiform Encephalopathies (TSE): Strategies to Detect, Reduce and Eliminate Infectivity in Biopharmaceuticals. Jerold Martin, Senior Vice President and Global Technical Director, Pall Corporation (NYSE:PLL) presents the latest data on the efficacy and applicability of a range of the Company's technologies to reduce prions associated with a number of fatal neurodegenerative diseases, including variant Creuztfeldt-Jakob Disease (vCJD) or "mad cow disease" in humans and Bovine Spongiform Encephalopathy (BSE) in cattle.

As new cases of BSE and vCJD continue to appear, including the recent cases of transfusion-related secondary transmission of vCJD, concerns have been mounting about therapeutics and diagnostics derived from animal and human tissues and blood.

"Reducing BSE contamination risk is a global effort that spans the entire food and drug supply chain," says Mr. Martin. "This effort starts with the elimination of animal tissues in animal feed and continues with the use of technologies that effectively remove prions from biological products and the blood supply. Pall is proud to be on the leading edge in the development of novel technologies to help solve this increasingly complex and challenging problem."

Pall's innovative filtration technologies address the breadth of contamination concerns by effectively removing prions from a wide range of biologicals. Mr. Martin's presentation focuses on the latest information on Pall technologies to remove prions from fluids and cells used in the manufacture of biological drugs and a new affinity technology in late stage testing to reduce all kinds of prions from blood prior to transfusion.

The U.S. Food and Drug Administration (FDA) is currently assessing prohibiting the use of bovine materials suspected of BSE contamination in the manufacture of regulated products. Although biotech companies are seeking new ways to develop protein-based therapies that are serum-free, many biological drugs, such as monoclonal antibodies (mAbs) and recombinant protein therapies, still use bovine serum-supplemented culture media. In response, an increasing number of pharmaceutical manufacturers are recognizing membrane filtration technology as an effective approach to help eliminate prions.

Mr. Martin provides several examples of the use of Pall technologies such as the Ultipor(R) VF grade DV20 and DV50 filters, which are used for removing viral contaminants during drug processing and have also demonstrated effective removal of prion proteins. He cites the recent example of the European Agency for the Evaluation of Medicinal Products (EMEA) qualification and approval of the Ultipor DV50 filter for prion removal for Redimune(R) immunoglobulin, manufactured by ZLB Bioplasma AG (Bern, Switzerland) and sold widely throughout Europe.

"The use of a barrier method, such as filtration, as opposed to prion inactivation, provides a more effective way of reducing prion contamination risks without compromising the integrity of the biological materials," Mr. Martin adds.

To address the growing concern of vCJD transmission through blood transfusion, Pall is in late stage testing of the Leukotrap(R) Affinity Prion Reduction Filter and expects to make the product available in Europe by the Spring. Mr. Martin provides an overview of the newest research results where the filter has been shown to remove different strains of infectious prions, including vCJD and scrapie, from red cell concentrates below the limit of detection of the Western blot assay. The innovative proprietary technology provides the dual benefit of reducing both leukocytes (white blood cells) and prions-- cell associated and non-cell associated -- in a single step. Pall expects to introduce the new filter commercially in Europe early next year followed by submission to the U.S. FDA and Health Canada. The company is also studying the filter as a device to aid in the detection of BSE in cattle before entering the food supply.

About Pall Corporation

Pall Corporation is the global leader in the rapidly growing field of filtration, separations and purification. Pall's business is organized around two broad markets: Life Sciences and Industrial. The Company provides leading-edge products to meet the demanding needs of customers in biotechnology, pharmaceutical, transfusion medicine, semiconductor, water purification, aerospace and broad industrial markets. Total revenues are $1.8 billion. The Company headquarters are in East Hills, New York with extensive operations throughout the world. Visit Pall at www.pall.com.

Editor's Notes:

Mr. Martin's presentation, "Filtration Technologies for Reducing Prion Contamination in Biologicals," takes place today at 1:45pm in the session "Novel Clearance and Inactivation Technologies to Reduce and Eliminate TSE Infectivity in Biopharmaceuticals" at the Hyatt Regency in Reston, VA.

Photos of Mr. Martin and some of the technologies he is showcasing can be found on www.pall.com/pressroom.

This release contains "forward-looking statements" as defined in the Private Securities Litigation Reform Act of 1995. These statements are based on current Company expectations and are subject to risk and uncertainties, which could cause actual results to differ materially. Such risks and uncertainties include, but are not limited to: fluctuations in foreign currency exchange rates; regulatory approval and market acceptance of new technologies; changes in product mix and product pricing and in interest rates and cost of raw materials; the Company's success in enforcing its patents and protecting its proprietary products and manufacturing techniques and its ability to achieve the savings anticipated from its cost reduction initiatives; global and regional economic conditions and legislative, regulatory and political developments; and domestic and international competition in the Company's global markets. Additional information regarding these and other factors is available on the Web at www.pall.com and is included in the Company's reports filed with the U.S. Securities and Exchange Commission. Copies of such reports can be obtained, without charge, at www.sec.gov.

Research Confirms that vCJD Prions Can be Removed from Blood; New Pall Technology Reduces Risk of Human-to-Human 'Mad Cow' Transmission by Transfusion

East Hills, N.Y., United States ( Monday, October 25 , 2004 05:32:00 PM)New research results released today confirm that infectious variant Creutzfeldt-Jakob Disease (vCJD) prions that cause the human form of "mad cow disease" can be removed from blood. The study, presented today at the annual meeting of the AABB, found that a new filtration technology from Pall Corporation (NYSE: PLL) reduces infectious vCJD prions from red blood cell concentrates, the most commonly transfused blood component.

The study, conducted at a leading prion research institute in Europe, found that the Pall Leukotrap(R) Affinity Prion Reduction Filter reduces infectious vCJD prions from red blood cell concentrates below the limit of detection of the Western blot assay. The investigators concluded that these results suggest that the new filter can be used to remove different strains of infectious prions, including vCJD.

Samuel O. Coker, Ph.D., Principal Scientist and Technical Director of Pall Medical, who presented the results also reported on the newest findings of additional research, conducted with the New York Institute of Basic Research, confirming that the same technology reduces infectious scrapie prions from blood. Both vCJD and scrapie are transmissible spongiform encephalopathies (TSEs) that cause fatal, neurorodegenerative prion diseases in humans and animals.

"The outcomes of these new studies are fortuitous in respect to the recent cases of transfusion-transmitted vCJD. The possibility of further increases in the number of human cases is of an uncertain magnitude, and the adverse impact that current donor deferral measures has on availability of the blood supply creates a serious public health issue" says Eric Krasnoff, Chairman and CEO, Pall Corporation. "We are moving forward as quickly as possible so that this new technology can be made available worldwide. This is part of our ongoing commitment to blood safety and our ongoing prion research program."

There have been two probable cases of human-to-human vCJD transmission via blood transfusions reported in the past year. Since there are no clinical signs or symptoms of the disease for many years, and the only reliable tests to determine who has the disease are performed post-mortem, there is no way of knowing how many people may be harboring vCJD and donating blood.

These events have spurred increasing concern about the possibility of a second and bigger wave of mad cow disease in humans. Public health officials and risk assessment experts believe that the problem is not limited to the UK, where a majority of the early cases of vCJD have been identified, or to Europe, but is a potential global threat that includes the U.S. and Canada. They urge that in addition to maintaining existing precautionary measures, additional risk assessments should be conducted for blood products in the U.S.

Reduction of vCJD and other TSEs from Blood

The study of vCJD used human red blood cell concentrates contaminated with about 10e8 (8 logs) infectious units of human vCJD from transgenic mice. The concentration of infectious vCJD prions in the red cell concentrates was measured before and after filtration with the Pall Leukotrap Prion Affinity Reduction Filter using a Western blot assay.

The research with infectious scrapie prions was a follow-up study that evaluated the efficacy of the filter to determine whether a test group of animals receiving the filtered red blood cells had the prion disease versus a control group that received the unfiltered red cells. The study confirmed that three (3) of the animals in the control group, which received the unfiltered scrapie infected blood, contracted scrapie as determined by post-mortem autopsy. None of the test group, which received the filtered blood, was found to have scrapie. Of the three controls where scrapie was confirmed, only two had previously displayed clinical symptoms of the disease. No animals in the test arm had any clinical signs of the disease.

"This latest research further confirms results from previous infectivity studies where it was found that this new technology removes TSE infected prions below the limit of detection of the Western blot assay," said Dr. Coker. "We are excited and optimistic about these results because it brings us much closer to helping ensure the safety of blood transfusion and preventing this insidious and devastating disease from escalating."

The Leukotrap Affinity Prion Reduction Filter's innovative proprietary technology is designed to provide the dual benefit of reducing both leukocytes (white blood cells) and infectious prions -- cell-associated and non-cell associated -- in a single step. About 60 percent of prion infectivity in blood resides in leukocytes (cell-associated) and about 40 percent in plasma (non-cell associated). The new filter also has an affinity to all types of prions including aggregated, denatured and normal.

Pall expects to launch the new filter in Europe in early 2005 with a Council of Europe (CE) mark. It is also developing a dossier and documentation to meet regulatory requirements for submission to the U.S. Food and Drug Administration in midyear 2005. Additionally, the Company is studying the filter as a device to aid in the detection of bovine spongiform encephalopathy (BSE) in cattle before entering the food supply.

The new filter is an integral component of the Pall Life Sciences technology platform, which provides several products to enhance the safety of the world's blood supply. Pall is the global leader in leukocyte reduction technology and also provides the enhanced Bacterial Detection System to test platelets for contamination prior to transfusion. The Company also provides products to remove infectious agents including viruses, bacteria and prions from biologicals used for the manufacture of medicines.

About Pall Corporation

Pall Corporation is the leader in the rapidly growing fields of filtration, separations and purification. Pall's business is organized around two broad markets: Life Sciences and Industrial. The Company provides leading-edge products to meet the demanding needs of customers in biotechnology, pharmaceuticals, transfusion medicine, semiconductors, municipal drinking water, aerospace and broad industrial markets. Total revenues are $1.77 billion. The Company headquarters are in East Hills, New York with operations in about 40 countries. Visit Pall at www.pall.com.

This release contains "forward-looking statements" as defined in the Private Securities Litigation Reform Act of 1995. These statements are based on current Company expectations and are subject to risk and uncertainties, which could cause actual results to differ materially. Such risks and uncertainties include, but are not limited to: fluctuations in foreign currency exchange rates; regulatory approval and market acceptance of new technologies; changes in product mix and product pricing and in interest rates and cost of raw materials; the Company's success in enforcing its patents and protecting its proprietary products and manufacturing techniques and its ability to achieve the savings anticipated from its cost reduction initiatives; global and regional economic conditions and legislative, regulatory and political developments; and domestic and international competition in the Company's global markets. Additional information regarding these and other factors is available on the Web at www.pall.com and is included in the Company's reports filed with the U.S. Securities and Exchange Commission. Copies of such reports can be obtained, without charge, at www.sec.gov.

Editor's notes:

-- Additional information and photos are available on www.pall.com/pressroom

-- Samuel O. Coker, Ph.D. is presenting the results of the two studies on Monday October 25th at 2:45 p.m., Baltimore Convention Center, Room 349/350 in an AABB scientific platform. He will repeat the highlights of these results in an evening symposium "TSEs--Measures to Reduce the Global Risk to the Blood Supply: Experts Present their Views" at 7:00 p.m. in the Grand Ballroom, Marriott Waterfront Hotel, Baltimore.

-- Media are invited to attend both events and interviews are available upon request. Media can also listen to the symposium by telephone. Call Susan Youdovin for reservations